includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  */
   6
   7 /** Number of times to re-try an operation in case of deadlock */
   8 define( 'DEADLOCK_TRIES', 4 );
   9 /** Minimum time to wait before retry, in microseconds */
  10 define( 'DEADLOCK_DELAY_MIN', 500000 );
  11 /** Maximum time to wait before retry */
  12 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  13
  14 /**
  15  * Database abstraction object
  16  * @addtogroup Database
  17  */
  18 class Database {
  19
  20 #------------------------------------------------------------------------------
  21 # Variables
  22 #------------------------------------------------------------------------------
  23
  24         protected $mLastQuery = '';
  25
  26         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  27         protected $mOut, $mOpened = false;
  28
  29         protected $mFailFunction;
  30         protected $mTablePrefix;
  31         protected $mFlags;
  32         protected $mTrxLevel = 0;
  33         protected $mErrorCount = 0;
  34         protected $mLBInfo = array();
  35         protected $mFakeSlaveLag = null, $mFakeMaster = false;
  36
  37 #------------------------------------------------------------------------------
  38 # Accessors
  39 #------------------------------------------------------------------------------
  40         # These optionally set a variable and return the previous state
  41
  42         /**
  43          * Fail function, takes a Database as a parameter
  44          * Set to false for default, 1 for ignore errors
  45          */
  46         function failFunction( $function = NULL ) {
  47                 return wfSetVar( $this->mFailFunction, $function );
  48         }
  49
  50         /**
  51          * Output page, used for reporting errors
  52          * FALSE means discard output
  53          */
  54         function setOutputPage( $out ) {
  55                 $this->mOut = $out;
  56         }
  57
  58         /**
  59          * Boolean, controls output of large amounts of debug information
  60          */
  61         function debug( $debug = NULL ) {
  62                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  63         }
  64
  65         /**
  66          * Turns buffering of SQL result sets on (true) or off (false).
  67          * Default is "on" and it should not be changed without good reasons.
  68          */
  69         function bufferResults( $buffer = NULL ) {
  70                 if ( is_null( $buffer ) ) {
  71                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
  72                 } else {
  73                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
  74                 }
  75         }
  76
  77         /**
  78          * Turns on (false) or off (true) the automatic generation and sending
  79          * of a "we're sorry, but there has been a database error" page on
  80          * database errors. Default is on (false). When turned off, the
  81          * code should use lastErrno() and lastError() to handle the
  82          * situation as appropriate.
  83          */
  84         function ignoreErrors( $ignoreErrors = NULL ) {
  85                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
  86         }
  87
  88         /**
  89          * The current depth of nested transactions
  90          * @param $level Integer: , default NULL.
  91          */
  92         function trxLevel( $level = NULL ) {
  93                 return wfSetVar( $this->mTrxLevel, $level );
  94         }
  95
  96         /**
  97          * Number of errors logged, only useful when errors are ignored
  98          */
  99         function errorCount( $count = NULL ) {
 100                 return wfSetVar( $this->mErrorCount, $count );
 101         }
 102
 103         function tablePrefix( $prefix = null ) {
 104                 return wfSetVar( $this->mTablePrefix, $prefix );
 105         }
 106
 107         /**
 108          * Properties passed down from the server info array of the load balancer
 109          */
 110         function getLBInfo( $name = NULL ) {
 111                 if ( is_null( $name ) ) {
 112                         return $this->mLBInfo;
 113                 } else {
 114                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 115                                 return $this->mLBInfo[$name];
 116                         } else {
 117                                 return NULL;
 118                         }
 119                 }
 120         }
 121
 122         function setLBInfo( $name, $value = NULL ) {
 123                 if ( is_null( $value ) ) {
 124                         $this->mLBInfo = $name;
 125                 } else {
 126                         $this->mLBInfo[$name] = $value;
 127                 }
 128         }
 129
 130         /**
 131          * Set lag time in seconds for a fake slave
 132          */
 133         function setFakeSlaveLag( $lag ) {
 134                 $this->mFakeSlaveLag = $lag;
 135         }
 136
 137         /**
 138          * Make this connection a fake master
 139          */
 140         function setFakeMaster( $enabled = true ) {
 141                 $this->mFakeMaster = $enabled;
 142         }
 143
 144         /**
 145          * Returns true if this database supports (and uses) cascading deletes
 146          */
 147         function cascadingDeletes() {
 148                 return false;
 149         }
 150
 151         /**
 152          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 153          */
 154         function cleanupTriggers() {
 155                 return false;
 156         }
 157
 158         /**
 159          * Returns true if this database is strict about what can be put into an IP field.
 160          * Specifically, it uses a NULL value instead of an empty string.
 161          */
 162         function strictIPs() {
 163                 return false;
 164         }
 165
 166         /**
 167          * Returns true if this database uses timestamps rather than integers
 168         */
 169         function realTimestamps() {
 170                 return false;
 171         }
 172
 173         /**
 174          * Returns true if this database does an implicit sort when doing GROUP BY
 175          */
 176         function implicitGroupby() {
 177                 return true;
 178         }
 179
 180         /**
 181          * Returns true if this database does an implicit order by when the column has an index
 182          * For example: SELECT page_title FROM page LIMIT 1
 183          */
 184         function implicitOrderby() {
 185                 return true;
 186         }
 187
 188         /**
 189          * Returns true if this database can do a native search on IP columns
 190          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 191          */
 192         function searchableIPs() {
 193                 return false;
 194         }
 195
 196         /**
 197          * Returns true if this database can use functional indexes
 198          */
 199         function functionalIndexes() {
 200                 return false;
 201         }
 202
 203         /**#@+
 204          * Get function
 205          */
 206         function lastQuery() { return $this->mLastQuery; }
 207         function isOpen() { return $this->mOpened; }
 208         /**#@-*/
 209
 210         function setFlag( $flag ) {
 211                 $this->mFlags |= $flag;
 212         }
 213
 214         function clearFlag( $flag ) {
 215                 $this->mFlags &= ~$flag;
 216         }
 217
 218         function getFlag( $flag ) {
 219                 return !!($this->mFlags & $flag);
 220         }
 221
 222         /**
 223          * General read-only accessor
 224          */
 225         function getProperty( $name ) {
 226                 return $this->$name;
 227         }
 228
 229 #------------------------------------------------------------------------------
 230 # Other functions
 231 #------------------------------------------------------------------------------
 232
 233         /**@{{
 234          * Constructor.
 235          * @param string $server database server host
 236          * @param string $user database user name
 237          * @param string $password database user password
 238          * @param string $dbname database name
 239          * @param failFunction
 240          * @param $flags
 241          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 242          */
 243         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 244                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 245
 246                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 247                 # Can't get a reference if it hasn't been set yet
 248                 if ( !isset( $wgOut ) ) {
 249                         $wgOut = NULL;
 250                 }
 251                 $this->mOut =& $wgOut;
 252
 253                 $this->mFailFunction = $failFunction;
 254                 $this->mFlags = $flags;
 255
 256                 if ( $this->mFlags & DBO_DEFAULT ) {
 257                         if ( $wgCommandLineMode ) {
 258                                 $this->mFlags &= ~DBO_TRX;
 259                         } else {
 260                                 $this->mFlags |= DBO_TRX;
 261                         }
 262                 }
 263
 264                 /*
 265                 // Faster read-only access
 266                 if ( wfReadOnly() ) {
 267                         $this->mFlags |= DBO_PERSISTENT;
 268                         $this->mFlags &= ~DBO_TRX;
 269                 }*/
 270
 271                 /** Get the default table prefix*/
 272                 if ( $tablePrefix == 'get from global' ) {
 273                         $this->mTablePrefix = $wgDBprefix;
 274                 } else {
 275                         $this->mTablePrefix = $tablePrefix;
 276                 }
 277
 278                 if ( $server ) {
 279                         $this->open( $server, $user, $password, $dbName );
 280                 }
 281         }
 282
 283         /**
 284          * @static
 285          * @param failFunction
 286          * @param $flags
 287          */
 288         static function newFromParams( $server, $user, $password, $dbName, $failFunction = false, $flags = 0 )
 289         {
 290                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 291         }
 292
 293         /**
 294          * Usually aborts on failure
 295          * If the failFunction is set to a non-zero integer, returns success
 296          */
 297         function open( $server, $user, $password, $dbName ) {
 298                 global $wguname;
 299                 wfProfileIn( __METHOD__ );
 300
 301                 $server = 'localhost'; debugging_code_left_in();
 302
 303                 # Test for missing mysql.so
 304                 # First try to load it
 305                 if (!@extension_loaded('mysql')) {
 306                         @dl('mysql.so');
 307                 }
 308
 309                 # Fail now
 310                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 311                 if ( !function_exists( 'mysql_connect' ) ) {
 312                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 313                 }
 314
 315                 $this->close();
 316                 $this->mServer = $server;
 317                 $this->mUser = $user;
 318                 $this->mPassword = $password;
 319                 $this->mDBname = $dbName;
 320
 321                 $success = false;
 322
 323                 wfProfileIn("dbconnect-$server");
 324
 325                 # Try to connect up to three times
 326                 # The kernel's default SYN retransmission period is far too slow for us,
 327                 # so we use a short timeout plus a manual retry.
 328                 $this->mConn = false;
 329                 $max = 3;
 330                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 331                         if ( $i > 1 ) {
 332                                 usleep( 1000 );
 333                         }
 334                         if ( $this->mFlags & DBO_PERSISTENT ) {
 335                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 336                         } else {
 337                                 # Create a new connection...
 338                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 339                         }
 340                         if ($this->mConn === false) {
 341                                 #$iplus = $i + 1;
 342                                 #wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 343                         }
 344                 }
 345
 346                 wfProfileOut("dbconnect-$server");
 347
 348                 if ( $dbName != '' ) {
 349                         if ( $this->mConn !== false ) {
 350                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 351                                 if ( !$success ) {
 352                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 353                                                 "from client host {$wguname['nodename']}\n";
 354                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 355                                         wfDebug( $error );
 356                                 }
 357                         } else {
 358                                 wfDebug( "DB connection error\n" );
 359                                 wfDebug( "Server: $server, User: $user, Password: " .
 360                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 361                                 $success = false;
 362                         }
 363                 } else {
 364                         # Delay USE query
 365                         $success = (bool)$this->mConn;
 366                 }
 367
 368                 if ( $success ) {
 369                         $version = $this->getServerVersion();
 370                         if ( version_compare( $version, '4.1' ) >= 0 ) {
 371                                 // Tell the server we're communicating with it in UTF-8.
 372                                 // This may engage various charset conversions.
 373                                 global $wgDBmysql5;
 374                                 if( $wgDBmysql5 ) {
 375                                         $this->query( 'SET NAMES utf8', __METHOD__ );
 376                                 }
 377                                 // Turn off strict mode
 378                                 $this->query( "SET sql_mode = ''", __METHOD__ );
 379                         }
 380
 381                         // Turn off strict mode if it is on
 382                 } else {
 383                         $this->reportConnectionError();
 384                 }
 385
 386                 $this->mOpened = $success;
 387                 wfProfileOut( __METHOD__ );
 388                 return $success;
 389         }
 390         /**@}}*/
 391
 392         /**
 393          * Closes a database connection.
 394          * if it is open : commits any open transactions
 395          *
 396          * @return bool operation success. true if already closed.
 397          */
 398         function close()
 399         {
 400                 $this->mOpened = false;
 401                 if ( $this->mConn ) {
 402                         if ( $this->trxLevel() ) {
 403                                 $this->immediateCommit();
 404                         }
 405                         return mysql_close( $this->mConn );
 406                 } else {
 407                         return true;
 408                 }
 409         }
 410
 411         /**
 412          * @param string $error fallback error message, used if none is given by MySQL
 413          */
 414         function reportConnectionError( $error = 'Unknown error' ) {
 415                 $myError = $this->lastError();
 416                 if ( $myError ) {
 417                         $error = $myError;
 418                 }
 419
 420                 if ( $this->mFailFunction ) {
 421                         # Legacy error handling method
 422                         if ( !is_int( $this->mFailFunction ) ) {
 423                                 $ff = $this->mFailFunction;
 424                                 $ff( $this, $error );
 425                         }
 426                 } else {
 427                         # New method
 428                         wfLogDBError( "Connection error: $error\n" );
 429                         throw new DBConnectionError( $this, $error );
 430                 }
 431         }
 432
 433         /**
 434          * Usually aborts on failure.  If errors are explicitly ignored, returns success.
 435          *
 436          * @param  $sql        String: SQL query
 437          * @param  $fname      String: Name of the calling function, for profiling/SHOW PROCESSLIST
 438          *     comment (you can use __METHOD__ or add some extra info)
 439          * @param  $tempIgnore Bool:   Whether to avoid throwing an exception on errors...
 440          *     maybe best to catch the exception instead?
 441          * @return true for a successful write query, ResultWrapper object for a successful read query,
 442          *     or false on failure if $tempIgnore set
 443          * @throws DBQueryError Thrown when the database returns an error of any kind
 444          */
 445         public function query( $sql, $fname = '', $tempIgnore = false ) {
 446                 global $wgProfiling;
 447
 448                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 449                 if ( $wgProfiling ) {
 450                         # generalizeSQL will probably cut down the query to reasonable
 451                         # logging size most of the time. The substr is really just a sanity check.
 452
 453                         # Who's been wasting my precious column space? -- TS
 454                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 455
 456                         if ( $isMaster ) {
 457                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 458                                 $totalProf = 'Database::query-master';
 459                         } else {
 460                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 461                                 $totalProf = 'Database::query';
 462                         }
 463                         wfProfileIn( $totalProf );
 464                         wfProfileIn( $queryProf );
 465                 }
 466
 467                 $this->mLastQuery = $sql;
 468
 469                 # Add a comment for easy SHOW PROCESSLIST interpretation
 470                 #if ( $fname ) {
 471                         global $wgUser;
 472                         if ( is_object( $wgUser ) && !($wgUser instanceof StubObject) ) {
 473                                 $userName = $wgUser->getName();
 474                                 if ( mb_strlen( $userName ) > 15 ) {
 475                                         $userName = mb_substr( $userName, 0, 15 ) . '...';
 476                                 }
 477                                 $userName = str_replace( '/', '', $userName );
 478                         } else {
 479                                 $userName = '';
 480                         }
 481                         $commentedSql = preg_replace('/\s/', " /* $fname $userName */ ", $sql, 1);
 482                 #} else {
 483                 #       $commentedSql = $sql;
 484                 #}
 485
 486                 # If DBO_TRX is set, start a transaction
 487                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 488                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK') {
 489                         // avoid establishing transactions for SHOW and SET statements too -
 490                         // that would delay transaction initializations to once connection
 491                         // is really used by application
 492                         $sqlstart = substr($sql,0,10); // very much worth it, benchmark certified(tm)
 493                         if (strpos($sqlstart,"SHOW ")!==0 and strpos($sqlstart,"SET ")!==0)
 494                                 $this->begin();
 495                 }
 496
 497                 if ( $this->debug() ) {
 498                         $sqlx = substr( $commentedSql, 0, 500 );
 499                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 500                         if ( $isMaster ) {
 501                                 wfDebug( "SQL-master: $sqlx\n" );
 502                         } else {
 503                                 wfDebug( "SQL: $sqlx\n" );
 504                         }
 505                 }
 506
 507                 # Do the query and handle errors
 508                 $ret = $this->doQuery( $commentedSql );
 509
 510                 # Try reconnecting if the connection was lost
 511                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 512                         # Transaction is gone, like it or not
 513                         $this->mTrxLevel = 0;
 514                         wfDebug( "Connection lost, reconnecting...\n" );
 515                         if ( $this->ping() ) {
 516                                 wfDebug( "Reconnected\n" );
 517                                 $sqlx = substr( $commentedSql, 0, 500 );
 518                                 $sqlx = strtr( $sqlx, "\t\n", '  ' );
 519                                 global $wgRequestTime;
 520                                 $elapsed = round( microtime(true) - $wgRequestTime, 3 );
 521                                 wfLogDBError( "Connection lost and reconnected after {$elapsed}s, query: $sqlx\n" );
 522                                 $ret = $this->doQuery( $commentedSql );
 523                         } else {
 524                                 wfDebug( "Failed\n" );
 525                         }
 526                 }
 527
 528                 if ( false === $ret ) {
 529                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 530                 }
 531
 532                 if ( $wgProfiling ) {
 533                         wfProfileOut( $queryProf );
 534                         wfProfileOut( $totalProf );
 535                 }
 536                 return $this->resultObject( $ret );
 537         }
 538
 539         /**
 540          * The DBMS-dependent part of query()
 541          * @param  $sql String: SQL query.
 542          * @return Result object to feed to fetchObject, fetchRow, ...; or false on failure
 543          * @access private
 544          */
 545         /*private*/ function doQuery( $sql ) {
 546                 if( $this->bufferResults() ) {
 547                         $ret = mysql_query( $sql, $this->mConn );
 548                 } else {
 549                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 550                 }
 551                 return $ret;
 552         }
 553
 554         /**
 555          * @param $error
 556          * @param $errno
 557          * @param $sql
 558          * @param string $fname
 559          * @param bool $tempIgnore
 560          */
 561         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 562                 global $wgCommandLineMode;
 563                 # Ignore errors during error handling to avoid infinite recursion
 564                 $ignore = $this->ignoreErrors( true );
 565                 ++$this->mErrorCount;
 566
 567                 if( $ignore || $tempIgnore ) {
 568                         wfDebug("SQL ERROR (ignored): $error\n");
 569                         $this->ignoreErrors( $ignore );
 570                 } else {
 571                         $sql1line = str_replace( "\n", "\\n", $sql );
 572                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 573                         wfDebug("SQL ERROR: " . $error . "\n");
 574                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 575                 }
 576         }
 577
 578
 579         /**
 580          * Intended to be compatible with the PEAR::DB wrapper functions.
 581          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 582          *
 583          * ? = scalar value, quoted as necessary
 584          * ! = raw SQL bit (a function for instance)
 585          * & = filename; reads the file and inserts as a blob
 586          *     (we don't use this though...)
 587          */
 588         function prepare( $sql, $func = 'Database::prepare' ) {
 589                 /* MySQL doesn't support prepared statements (yet), so just
 590                    pack up the query for reference. We'll manually replace
 591                    the bits later. */
 592                 return array( 'query' => $sql, 'func' => $func );
 593         }
 594
 595         function freePrepared( $prepared ) {
 596                 /* No-op for MySQL */
 597         }
 598
 599         /**
 600          * Execute a prepared query with the various arguments
 601          * @param string $prepared the prepared sql
 602          * @param mixed $args Either an array here, or put scalars as varargs
 603          */
 604         function execute( $prepared, $args = null ) {
 605                 if( !is_array( $args ) ) {
 606                         # Pull the var args
 607                         $args = func_get_args();
 608                         array_shift( $args );
 609                 }
 610                 $sql = $this->fillPrepared( $prepared['query'], $args );
 611                 return $this->query( $sql, $prepared['func'] );
 612         }
 613
 614         /**
 615          * Prepare & execute an SQL statement, quoting and inserting arguments
 616          * in the appropriate places.
 617          * @param string $query
 618          * @param string $args ...
 619          */
 620         function safeQuery( $query, $args = null ) {
 621                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 622                 if( !is_array( $args ) ) {
 623                         # Pull the var args
 624                         $args = func_get_args();
 625                         array_shift( $args );
 626                 }
 627                 $retval = $this->execute( $prepared, $args );
 628                 $this->freePrepared( $prepared );
 629                 return $retval;
 630         }
 631
 632         /**
 633          * For faking prepared SQL statements on DBs that don't support
 634          * it directly.
 635          * @param string $preparedSql - a 'preparable' SQL statement
 636          * @param array $args - array of arguments to fill it with
 637          * @return string executable SQL
 638          */
 639         function fillPrepared( $preparedQuery, $args ) {
 640                 reset( $args );
 641                 $this->preparedArgs =& $args;
 642                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 643                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 644         }
 645
 646         /**
 647          * preg_callback func for fillPrepared()
 648          * The arguments should be in $this->preparedArgs and must not be touched
 649          * while we're doing this.
 650          *
 651          * @param array $matches
 652          * @return string
 653          * @private
 654          */
 655         function fillPreparedArg( $matches ) {
 656                 switch( $matches[1] ) {
 657                         case '\\?': return '?';
 658                         case '\\!': return '!';
 659                         case '\\&': return '&';
 660                 }
 661                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 662                 switch( $matches[1] ) {
 663                         case '?': return $this->addQuotes( $arg );
 664                         case '!': return $arg;
 665                         case '&':
 666                                 # return $this->addQuotes( file_get_contents( $arg ) );
 667                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 668                         default:
 669                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 670                 }
 671         }
 672
 673         /**#@+
 674          * @param mixed $res A SQL result
 675          */
 676         /**
 677          * Free a result object
 678          */
 679         function freeResult( $res ) {
 680                 if ( $res instanceof ResultWrapper ) {
 681                         $res = $res->result;
 682                 }
 683                 if ( !@/**/mysql_free_result( $res ) ) {
 684                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 685                 }
 686         }
 687
 688         /**
 689          * Fetch the next row from the given result object, in object form.
 690          * Fields can be retrieved with $row->fieldname, with fields acting like
 691          * member variables.
 692          *
 693          * @param $res SQL result object as returned from Database::query(), etc.
 694          * @return MySQL row object
 695          * @throws DBUnexpectedError Thrown if the database returns an error
 696          */
 697         function fetchObject( $res ) {
 698                 if ( $res instanceof ResultWrapper ) {
 699                         $res = $res->result;
 700                 }
 701                 @/**/$row = mysql_fetch_object( $res );
 702                 if( $this->lastErrno() ) {
 703                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 704                 }
 705                 return $row;
 706         }
 707
 708         /**
 709          * Fetch the next row from the given result object, in associative array
 710          * form.  Fields are retrieved with $row['fieldname'].
 711          *
 712          * @param $res SQL result object as returned from Database::query(), etc.
 713          * @return MySQL row object
 714          * @throws DBUnexpectedError Thrown if the database returns an error
 715          */
 716         function fetchRow( $res ) {
 717                 if ( $res instanceof ResultWrapper ) {
 718                         $res = $res->result;
 719                 }
 720                 @/**/$row = mysql_fetch_array( $res );
 721                 if ( $this->lastErrno() ) {
 722                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 723                 }
 724                 return $row;
 725         }
 726
 727         /**
 728          * Get the number of rows in a result object
 729          */
 730         function numRows( $res ) {
 731                 if ( $res instanceof ResultWrapper ) {
 732                         $res = $res->result;
 733                 }
 734                 @/**/$n = mysql_num_rows( $res );
 735                 if( $this->lastErrno() ) {
 736                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 737                 }
 738                 return $n;
 739         }
 740
 741         /**
 742          * Get the number of fields in a result object
 743          * See documentation for mysql_num_fields()
 744          */
 745         function numFields( $res ) {
 746                 if ( $res instanceof ResultWrapper ) {
 747                         $res = $res->result;
 748                 }
 749                 return mysql_num_fields( $res );
 750         }
 751
 752         /**
 753          * Get a field name in a result object
 754          * See documentation for mysql_field_name():
 755          * http://www.php.net/mysql_field_name
 756          */
 757         function fieldName( $res, $n ) {
 758                 if ( $res instanceof ResultWrapper ) {
 759                         $res = $res->result;
 760                 }
 761                 return mysql_field_name( $res, $n );
 762         }
 763
 764         /**
 765          * Get the inserted value of an auto-increment row
 766          *
 767          * The value inserted should be fetched from nextSequenceValue()
 768          *
 769          * Example:
 770          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 771          * $dbw->insert('page',array('page_id' => $id));
 772          * $id = $dbw->insertId();
 773          */
 774         function insertId() { return mysql_insert_id( $this->mConn ); }
 775
 776         /**
 777          * Change the position of the cursor in a result object
 778          * See mysql_data_seek()
 779          */
 780         function dataSeek( $res, $row ) {
 781                 if ( $res instanceof ResultWrapper ) {
 782                         $res = $res->result;
 783                 }
 784                 return mysql_data_seek( $res, $row );
 785         }
 786
 787         /**
 788          * Get the last error number
 789          * See mysql_errno()
 790          */
 791         function lastErrno() {
 792                 if ( $this->mConn ) {
 793                         return mysql_errno( $this->mConn );
 794                 } else {
 795                         return mysql_errno();
 796                 }
 797         }
 798
 799         /**
 800          * Get a description of the last error
 801          * See mysql_error() for more details
 802          */
 803         function lastError() {
 804                 if ( $this->mConn ) {
 805                         # Even if it's non-zero, it can still be invalid
 806                         wfSuppressWarnings();
 807                         $error = mysql_error( $this->mConn );
 808                         if ( !$error ) {
 809                                 $error = mysql_error();
 810                         }
 811                         wfRestoreWarnings();
 812                 } else {
 813                         $error = mysql_error();
 814                 }
 815                 if( $error ) {
 816                         $error .= ' (' . $this->mServer . ')';
 817                 }
 818                 return $error;
 819         }
 820         /**
 821          * Get the number of rows affected by the last write query
 822          * See mysql_affected_rows() for more details
 823          */
 824         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 825         /**#@-*/ // end of template : @param $result
 826
 827         /**
 828          * Simple UPDATE wrapper
 829          * Usually aborts on failure
 830          * If errors are explicitly ignored, returns success
 831          *
 832          * This function exists for historical reasons, Database::update() has a more standard
 833          * calling convention and feature set
 834          */
 835         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 836         {
 837                 $table = $this->tableName( $table );
 838                 $sql = "UPDATE $table SET $var = '" .
 839                   $this->strencode( $value ) . "' WHERE ($cond)";
 840                 return (bool)$this->query( $sql, $fname );
 841         }
 842
 843         /**
 844          * Simple SELECT wrapper, returns a single field, input must be encoded
 845          * Usually aborts on failure
 846          * If errors are explicitly ignored, returns FALSE on failure
 847          */
 848         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 849                 if ( !is_array( $options ) ) {
 850                         $options = array( $options );
 851                 }
 852                 $options['LIMIT'] = 1;
 853
 854                 $res = $this->select( $table, $var, $cond, $fname, $options );
 855                 if ( $res === false || !$this->numRows( $res ) ) {
 856                         return false;
 857                 }
 858                 $row = $this->fetchRow( $res );
 859                 if ( $row !== false ) {
 860                         $this->freeResult( $res );
 861                         return $row[0];
 862                 } else {
 863                         return false;
 864                 }
 865         }
 866
 867         /**
 868          * Returns an optional USE INDEX clause to go after the table, and a
 869          * string to go at the end of the query
 870          *
 871          * @private
 872          *
 873          * @param array $options an associative array of options to be turned into
 874          *              an SQL query, valid keys are listed in the function.
 875          * @return array
 876          */
 877         function makeSelectOptions( $options ) {
 878                 $preLimitTail = $postLimitTail = '';
 879                 $startOpts = '';
 880
 881                 $noKeyOptions = array();
 882                 foreach ( $options as $key => $option ) {
 883                         if ( is_numeric( $key ) ) {
 884                                 $noKeyOptions[$option] = true;
 885                         }
 886                 }
 887
 888                 if ( isset( $options['GROUP BY'] ) ) $preLimitTail .= " GROUP BY {$options['GROUP BY']}";
 889                 if ( isset( $options['HAVING'] ) ) $preLimitTail .= " HAVING {$options['HAVING']}";
 890                 if ( isset( $options['ORDER BY'] ) ) $preLimitTail .= " ORDER BY {$options['ORDER BY']}";
 891
 892                 //if (isset($options['LIMIT'])) {
 893                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
 894                 //              isset($options['OFFSET']) ? $options['OFFSET']
 895                 //              : false);
 896                 //}
 897
 898                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $postLimitTail .= ' FOR UPDATE';
 899                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $postLimitTail .= ' LOCK IN SHARE MODE';
 900                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 901
 902                 # Various MySQL extensions
 903                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 904                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 905                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 906                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 907                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 908                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 909                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 910                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 911
 912                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 913                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 914                 } else {
 915                         $useIndex = '';
 916                 }
 917
 918                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
 919         }
 920
 921         /**
 922          * SELECT wrapper
 923          *
 924          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
 925          * @param mixed  $vars    Array or string, field name(s) to be retrieved
 926          * @param mixed  $conds   Array or string, condition(s) for WHERE
 927          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
 928          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 929          *                        see Database::makeSelectOptions code for list of supported stuff
 930          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
 931          */
 932         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 933         {
 934                 if( is_array( $vars ) ) {
 935                         $vars = implode( ',', $vars );
 936                 }
 937                 if( !is_array( $options ) ) {
 938                         $options = array( $options );
 939                 }
 940                 if( is_array( $table ) ) {
 941                         if ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
 942                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
 943                         else
 944                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 945                 } elseif ($table!='') {
 946                         if ($table{0}==' ') {
 947                                 $from = ' FROM ' . $table;
 948                         } else {
 949                                 $from = ' FROM ' . $this->tableName( $table );
 950                         }
 951                 } else {
 952                         $from = '';
 953                 }
 954
 955                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) = $this->makeSelectOptions( $options );
 956
 957                 if( !empty( $conds ) ) {
 958                         if ( is_array( $conds ) ) {
 959                                 $conds = $this->makeList( $conds, LIST_AND );
 960                         }
 961                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
 962                 } else {
 963                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
 964                 }
 965
 966                 if (isset($options['LIMIT']))
 967                         $sql = $this->limitResult($sql, $options['LIMIT'],
 968                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 969                 $sql = "$sql $postLimitTail";
 970
 971                 if (isset($options['EXPLAIN'])) {
 972                         $sql = 'EXPLAIN ' . $sql;
 973                 }
 974                 return $this->query( $sql, $fname );
 975         }
 976
 977         /**
 978          * Single row SELECT wrapper
 979          * Aborts or returns FALSE on error
 980          *
 981          * $vars: the selected variables
 982          * $conds: a condition map, terms are ANDed together.
 983          *   Items with numeric keys are taken to be literal conditions
 984          * Takes an array of selected variables, and a condition map, which is ANDed
 985          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 986          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 987          * $obj- >page_id is the ID of the Astronomy article
 988          *
 989          * @todo migrate documentation to phpdocumentor format
 990          */
 991         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 992                 $options['LIMIT'] = 1;
 993                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 994                 if ( $res === false )
 995                         return false;
 996                 if ( !$this->numRows($res) ) {
 997                         $this->freeResult($res);
 998                         return false;
 999                 }
1000                 $obj = $this->fetchObject( $res );
1001                 $this->freeResult( $res );
1002                 return $obj;
1003
1004         }
1005
1006         /**
1007          * Estimate rows in dataset
1008          * Returns estimated count, based on EXPLAIN output
1009          * Takes same arguments as Database::select()
1010          */
1011
1012         function estimateRowCount( $table, $vars='*', $conds='', $fname = 'Database::estimateRowCount', $options = array() ) {
1013                 $options['EXPLAIN']=true;
1014                 $res = $this->select ($table, $vars, $conds, $fname, $options );
1015                 if ( $res === false )
1016                         return false;
1017                 if (!$this->numRows($res)) {
1018                         $this->freeResult($res);
1019                         return 0;
1020                 }
1021
1022                 $rows=1;
1023
1024                 while( $plan = $this->fetchObject( $res ) ) {
1025                         $rows *= ($plan->rows > 0)?$plan->rows:1; // avoid resetting to zero
1026                 }
1027
1028                 $this->freeResult($res);
1029                 return $rows;
1030         }
1031
1032
1033         /**
1034          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1035          * It's only slightly flawed. Don't use for anything important.
1036          *
1037          * @param string $sql A SQL Query
1038          * @static
1039          */
1040         static function generalizeSQL( $sql ) {
1041                 # This does the same as the regexp below would do, but in such a way
1042                 # as to avoid crashing php on some large strings.
1043                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1044
1045                 $sql = str_replace ( "\\\\", '', $sql);
1046                 $sql = str_replace ( "\\'", '', $sql);
1047                 $sql = str_replace ( "\\\"", '', $sql);
1048                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1049                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1050
1051                 # All newlines, tabs, etc replaced by single space
1052                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1053
1054                 # All numbers => N
1055                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1056
1057                 return $sql;
1058         }
1059
1060         /**
1061          * Determines whether a field exists in a table
1062          * Usually aborts on failure
1063          * If errors are explicitly ignored, returns NULL on failure
1064          */
1065         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1066                 $table = $this->tableName( $table );
1067                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1068                 if ( !$res ) {
1069                         return NULL;
1070                 }
1071
1072                 $found = false;
1073
1074                 while ( $row = $this->fetchObject( $res ) ) {
1075                         if ( $row->Field == $field ) {
1076                                 $found = true;
1077                                 break;
1078                         }
1079                 }
1080                 return $found;
1081         }
1082
1083         /**
1084          * Determines whether an index exists
1085          * Usually aborts on failure
1086          * If errors are explicitly ignored, returns NULL on failure
1087          */
1088         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1089                 $info = $this->indexInfo( $table, $index, $fname );
1090                 if ( is_null( $info ) ) {
1091                         return NULL;
1092                 } else {
1093                         return $info !== false;
1094                 }
1095         }
1096
1097
1098         /**
1099          * Get information about an index into an object
1100          * Returns false if the index does not exist
1101          */
1102         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1103                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1104                 # SHOW INDEX should work for 3.x and up:
1105                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1106                 $table = $this->tableName( $table );
1107                 $sql = 'SHOW INDEX FROM '.$table;
1108                 $res = $this->query( $sql, $fname );
1109                 if ( !$res ) {
1110                         return NULL;
1111                 }
1112
1113                 $result = array();
1114                 while ( $row = $this->fetchObject( $res ) ) {
1115                         if ( $row->Key_name == $index ) {
1116                                 $result[] = $row;
1117                         }
1118                 }
1119                 $this->freeResult($res);
1120
1121                 return empty($result) ? false : $result;
1122         }
1123
1124         /**
1125          * Query whether a given table exists
1126          */
1127         function tableExists( $table ) {
1128                 $table = $this->tableName( $table );
1129                 $old = $this->ignoreErrors( true );
1130                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1131                 $this->ignoreErrors( $old );
1132                 if( $res ) {
1133                         $this->freeResult( $res );
1134                         return true;
1135                 } else {
1136                         return false;
1137                 }
1138         }
1139
1140         /**
1141          * mysql_fetch_field() wrapper
1142          * Returns false if the field doesn't exist
1143          *
1144          * @param $table
1145          * @param $field
1146          */
1147         function fieldInfo( $table, $field ) {
1148                 $table = $this->tableName( $table );
1149                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1150                 $n = mysql_num_fields( $res->result );
1151                 for( $i = 0; $i < $n; $i++ ) {
1152                         $meta = mysql_fetch_field( $res->result, $i );
1153                         if( $field == $meta->name ) {
1154                                 return new MySQLField($meta);
1155                         }
1156                 }
1157                 return false;
1158         }
1159
1160         /**
1161          * mysql_field_type() wrapper
1162          */
1163         function fieldType( $res, $index ) {
1164                 if ( $res instanceof ResultWrapper ) {
1165                         $res = $res->result;
1166                 }
1167                 return mysql_field_type( $res, $index );
1168         }
1169
1170         /**
1171          * Determines if a given index is unique
1172          */
1173         function indexUnique( $table, $index ) {
1174                 $indexInfo = $this->indexInfo( $table, $index );
1175                 if ( !$indexInfo ) {
1176                         return NULL;
1177                 }
1178                 return !$indexInfo[0]->Non_unique;
1179         }
1180
1181         /**
1182          * INSERT wrapper, inserts an array into a table
1183          *
1184          * $a may be a single associative array, or an array of these with numeric keys, for
1185          * multi-row insert.
1186          *
1187          * Usually aborts on failure
1188          * If errors are explicitly ignored, returns success
1189          */
1190         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1191                 # No rows to insert, easy just return now
1192                 if ( !count( $a ) ) {
1193                         return true;
1194                 }
1195
1196                 $table = $this->tableName( $table );
1197                 if ( !is_array( $options ) ) {
1198                         $options = array( $options );
1199                 }
1200                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1201                         $multi = true;
1202                         $keys = array_keys( $a[0] );
1203                 } else {
1204                         $multi = false;
1205                         $keys = array_keys( $a );
1206                 }
1207
1208                 $sql = 'INSERT ' . implode( ' ', $options ) .
1209                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1210
1211                 if ( $multi ) {
1212                         $first = true;
1213                         foreach ( $a as $row ) {
1214                                 if ( $first ) {
1215                                         $first = false;
1216                                 } else {
1217                                         $sql .= ',';
1218                                 }
1219                                 $sql .= '(' . $this->makeList( $row ) . ')';
1220                         }
1221                 } else {
1222                         $sql .= '(' . $this->makeList( $a ) . ')';
1223                 }
1224                 return (bool)$this->query( $sql, $fname );
1225         }
1226
1227         /**
1228          * Make UPDATE options for the Database::update function
1229          *
1230          * @private
1231          * @param array $options The options passed to Database::update
1232          * @return string
1233          */
1234         function makeUpdateOptions( $options ) {
1235                 if( !is_array( $options ) ) {
1236                         $options = array( $options );
1237                 }
1238                 $opts = array();
1239                 if ( in_array( 'LOW_PRIORITY', $options ) )
1240                         $opts[] = $this->lowPriorityOption();
1241                 if ( in_array( 'IGNORE', $options ) )
1242                         $opts[] = 'IGNORE';
1243                 return implode(' ', $opts);
1244         }
1245
1246         /**
1247          * UPDATE wrapper, takes a condition array and a SET array
1248          *
1249          * @param string $table  The table to UPDATE
1250          * @param array  $values An array of values to SET
1251          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1252          * @param string $fname  The Class::Function calling this function
1253          *                       (for the log)
1254          * @param array  $options An array of UPDATE options, can be one or
1255          *                        more of IGNORE, LOW_PRIORITY
1256          * @return bool
1257          */
1258         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1259                 $table = $this->tableName( $table );
1260                 $opts = $this->makeUpdateOptions( $options );
1261                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1262                 if ( $conds != '*' ) {
1263                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1264                 }
1265                 return $this->query( $sql, $fname );
1266         }
1267
1268         /**
1269          * Makes an encoded list of strings from an array
1270          * $mode:
1271          *        LIST_COMMA         - comma separated, no field names
1272          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1273          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1274          *        LIST_SET           - comma separated with field names, like a SET clause
1275          *        LIST_NAMES         - comma separated field names
1276          */
1277         function makeList( $a, $mode = LIST_COMMA ) {
1278                 if ( !is_array( $a ) ) {
1279                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1280                 }
1281
1282                 $first = true;
1283                 $list = '';
1284                 foreach ( $a as $field => $value ) {
1285                         if ( !$first ) {
1286                                 if ( $mode == LIST_AND ) {
1287                                         $list .= ' AND ';
1288                                 } elseif($mode == LIST_OR) {
1289                                         $list .= ' OR ';
1290                                 } else {
1291                                         $list .= ',';
1292                                 }
1293                         } else {
1294                                 $first = false;
1295                         }
1296                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1297                                 $list .= "($value)";
1298                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1299                                 $list .= "$value";
1300                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array($value) ) {
1301                                 if( count( $value ) == 0 ) {
1302                                         throw new MWException( __METHOD__.': empty input' );
1303                                 } elseif( count( $value ) == 1 ) {
1304                                         // Special-case single values, as IN isn't terribly efficient
1305                                         // Don't necessarily assume the single key is 0; we don't
1306                                         // enforce linear numeric ordering on other arrays here.
1307                                         $value = array_values( $value );
1308                                         $list .= $field." = ".$this->addQuotes( $value[0] );
1309                                 } else {
1310                                         $list .= $field." IN (".$this->makeList($value).") ";
1311                                 }
1312                         } elseif( is_null($value) ) {
1313                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1314                                         $list .= "$field IS ";
1315                                 } elseif ( $mode == LIST_SET ) {
1316                                         $list .= "$field = ";
1317                                 }
1318                                 $list .= 'NULL';
1319                         } else {
1320                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1321                                         $list .= "$field = ";
1322                                 }
1323                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1324                         }
1325                 }
1326                 return $list;
1327         }
1328
1329         /**
1330          * Change the current database
1331          */
1332         function selectDB( $db ) {
1333                 $this->mDBname = $db;
1334                 return mysql_select_db( $db, $this->mConn );
1335         }
1336
1337         /**
1338          * Get the current DB name
1339          */
1340         function getDBname() {
1341                 return $this->mDBname;
1342         }
1343
1344         /**
1345          * Get the server hostname or IP address
1346          */
1347         function getServer() {
1348                 return $this->mServer;
1349         }
1350
1351         /**
1352          * Format a table name ready for use in constructing an SQL query
1353          *
1354          * This does two important things: it quotes table names which as necessary,
1355          * and it adds a table prefix if there is one.
1356          *
1357          * All functions of this object which require a table name call this function
1358          * themselves. Pass the canonical name to such functions. This is only needed
1359          * when calling query() directly.
1360          *
1361          * @param string $name database table name
1362          */
1363         function tableName( $name ) {
1364                 global $wgSharedDB;
1365                 # Skip quoted literals
1366                 if ( $name{0} != '`' ) {
1367                         if ( $this->mTablePrefix !== '' &&  strpos( $name, '.' ) === false ) {
1368                                 $name = "{$this->mTablePrefix}$name";
1369                         }
1370                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1371                                 $name = "`$wgSharedDB`.`$name`";
1372                         } else {
1373                                 # Standard quoting
1374                                 $name = "`$name`";
1375                         }
1376                 }
1377                 return $name;
1378         }
1379
1380         /**
1381          * Fetch a number of table names into an array
1382          * This is handy when you need to construct SQL for joins
1383          *
1384          * Example:
1385          * extract($dbr->tableNames('user','watchlist'));
1386          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1387          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1388          */
1389         public function tableNames() {
1390                 $inArray = func_get_args();
1391                 $retVal = array();
1392                 foreach ( $inArray as $name ) {
1393                         $retVal[$name] = $this->tableName( $name );
1394                 }
1395                 return $retVal;
1396         }
1397
1398         /**
1399          * Fetch a number of table names into an zero-indexed numerical array
1400          * This is handy when you need to construct SQL for joins
1401          *
1402          * Example:
1403          * list( $user, $watchlist ) = $dbr->tableNamesN('user','watchlist');
1404          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1405          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1406          */
1407         public function tableNamesN() {
1408                 $inArray = func_get_args();
1409                 $retVal = array();
1410                 foreach ( $inArray as $name ) {
1411                         $retVal[] = $this->tableName( $name );
1412                 }
1413                 return $retVal;
1414         }
1415
1416         /**
1417          * @private
1418          */
1419         function tableNamesWithUseIndex( $tables, $use_index ) {
1420                 $ret = array();
1421
1422                 foreach ( $tables as $table )
1423                         if ( @$use_index[$table] !== null )
1424                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1425                         else
1426                                 $ret[] = $this->tableName( $table );
1427
1428                 return implode( ',', $ret );
1429         }
1430
1431         /**
1432          * Wrapper for addslashes()
1433          * @param string $s String to be slashed.
1434          * @return string slashed string.
1435          */
1436         function strencode( $s ) {
1437                 return mysql_real_escape_string( $s, $this->mConn );
1438         }
1439
1440         /**
1441          * If it's a string, adds quotes and backslashes
1442          * Otherwise returns as-is
1443          */
1444         function addQuotes( $s ) {
1445                 if ( is_null( $s ) ) {
1446                         return 'NULL';
1447                 } else {
1448                         # This will also quote numeric values. This should be harmless,
1449                         # and protects against weird problems that occur when they really
1450                         # _are_ strings such as article titles and string->number->string
1451                         # conversion is not 1:1.
1452                         return "'" . $this->strencode( $s ) . "'";
1453                 }
1454         }
1455
1456         /**
1457          * Escape string for safe LIKE usage
1458          */
1459         function escapeLike( $s ) {
1460                 $s=$this->strencode( $s );
1461                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1462                 return $s;
1463         }
1464
1465         /**
1466          * Returns an appropriately quoted sequence value for inserting a new row.
1467          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1468          * subclass will return an integer, and save the value for insertId()
1469          */
1470         function nextSequenceValue( $seqName ) {
1471                 return NULL;
1472         }
1473
1474         /**
1475          * USE INDEX clause
1476          * PostgreSQL doesn't have them and returns ""
1477          */
1478         function useIndexClause( $index ) {
1479                 return "FORCE INDEX ($index)";
1480         }
1481
1482         /**
1483          * REPLACE query wrapper
1484          * PostgreSQL simulates this with a DELETE followed by INSERT
1485          * $row is the row to insert, an associative array
1486          * $uniqueIndexes is an array of indexes. Each element may be either a
1487          * field name or an array of field names
1488          *
1489          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1490          * However if you do this, you run the risk of encountering errors which wouldn't have
1491          * occurred in MySQL
1492          *
1493          * @todo migrate comment to phodocumentor format
1494          */
1495         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1496                 $table = $this->tableName( $table );
1497
1498                 # Single row case
1499                 if ( !is_array( reset( $rows ) ) ) {
1500                         $rows = array( $rows );
1501                 }
1502
1503                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1504                 $first = true;
1505                 foreach ( $rows as $row ) {
1506                         if ( $first ) {
1507                                 $first = false;
1508                         } else {
1509                                 $sql .= ',';
1510                         }
1511                         $sql .= '(' . $this->makeList( $row ) . ')';
1512                 }
1513                 return $this->query( $sql, $fname );
1514         }
1515
1516         /**
1517          * DELETE where the condition is a join
1518          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1519          *
1520          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1521          * join condition matches, set $conds='*'
1522          *
1523          * DO NOT put the join condition in $conds
1524          *
1525          * @param string $delTable The table to delete from.
1526          * @param string $joinTable The other table.
1527          * @param string $delVar The variable to join on, in the first table.
1528          * @param string $joinVar The variable to join on, in the second table.
1529          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1530          */
1531         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1532                 if ( !$conds ) {
1533                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1534                 }
1535
1536                 $delTable = $this->tableName( $delTable );
1537                 $joinTable = $this->tableName( $joinTable );
1538                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1539                 if ( $conds != '*' ) {
1540                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1541                 }
1542
1543                 return $this->query( $sql, $fname );
1544         }
1545
1546         /**
1547          * Returns the size of a text field, or -1 for "unlimited"
1548          */
1549         function textFieldSize( $table, $field ) {
1550                 $table = $this->tableName( $table );
1551                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1552                 $res = $this->query( $sql, 'Database::textFieldSize' );
1553                 $row = $this->fetchObject( $res );
1554                 $this->freeResult( $res );
1555
1556                 $m = array();
1557                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1558                         $size = $m[1];
1559                 } else {
1560                         $size = -1;
1561                 }
1562                 return $size;
1563         }
1564
1565         /**
1566          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1567          */
1568         function lowPriorityOption() {
1569                 return 'LOW_PRIORITY';
1570         }
1571
1572         /**
1573          * DELETE query wrapper
1574          *
1575          * Use $conds == "*" to delete all rows
1576          */
1577         function delete( $table, $conds, $fname = 'Database::delete' ) {
1578                 if ( !$conds ) {
1579                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1580                 }
1581                 $table = $this->tableName( $table );
1582                 $sql = "DELETE FROM $table";
1583                 if ( $conds != '*' ) {
1584                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1585                 }
1586                 return $this->query( $sql, $fname );
1587         }
1588
1589         /**
1590          * INSERT SELECT wrapper
1591          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1592          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1593          * $conds may be "*" to copy the whole table
1594          * srcTable may be an array of tables.
1595          */
1596         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1597                 $insertOptions = array(), $selectOptions = array() )
1598         {
1599                 $destTable = $this->tableName( $destTable );
1600                 if ( is_array( $insertOptions ) ) {
1601                         $insertOptions = implode( ' ', $insertOptions );
1602                 }
1603                 if( !is_array( $selectOptions ) ) {
1604                         $selectOptions = array( $selectOptions );
1605                 }
1606                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1607                 if( is_array( $srcTable ) ) {
1608                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1609                 } else {
1610                         $srcTable = $this->tableName( $srcTable );
1611                 }
1612                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1613                         " SELECT $startOpts " . implode( ',', $varMap ) .
1614                         " FROM $srcTable $useIndex ";
1615                 if ( $conds != '*' ) {
1616                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1617                 }
1618                 $sql .= " $tailOpts";
1619                 return $this->query( $sql, $fname );
1620         }
1621
1622         /**
1623          * Construct a LIMIT query with optional offset
1624          * This is used for query pages
1625          * $sql string SQL query we will append the limit too
1626          * $limit integer the SQL limit
1627          * $offset integer the SQL offset (default false)
1628          */
1629         function limitResult($sql, $limit, $offset=false) {
1630                 if( !is_numeric($limit) ) {
1631                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1632                 }
1633                 return " $sql LIMIT "
1634                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1635                                 . "{$limit} ";
1636         }
1637         function limitResultForUpdate($sql, $num) {
1638                 return $this->limitResult($sql, $num, 0);
1639         }
1640
1641         /**
1642          * Returns an SQL expression for a simple conditional.
1643          * Uses IF on MySQL.
1644          *
1645          * @param string $cond SQL expression which will result in a boolean value
1646          * @param string $trueVal SQL expression to return if true
1647          * @param string $falseVal SQL expression to return if false
1648          * @return string SQL fragment
1649          */
1650         function conditional( $cond, $trueVal, $falseVal ) {
1651                 return " IF($cond, $trueVal, $falseVal) ";
1652         }
1653
1654         /**
1655          * Determines if the last failure was due to a deadlock
1656          */
1657         function wasDeadlock() {
1658                 return $this->lastErrno() == 1213;
1659         }
1660
1661         /**
1662          * Perform a deadlock-prone transaction.
1663          *
1664          * This function invokes a callback function to perform a set of write
1665          * queries. If a deadlock occurs during the processing, the transaction
1666          * will be rolled back and the callback function will be called again.
1667          *
1668          * Usage:
1669          *   $dbw->deadlockLoop( callback, ... );
1670          *
1671          * Extra arguments are passed through to the specified callback function.
1672          *
1673          * Returns whatever the callback function returned on its successful,
1674          * iteration, or false on error, for example if the retry limit was
1675          * reached.
1676          */
1677         function deadlockLoop() {
1678                 $myFname = 'Database::deadlockLoop';
1679
1680                 $this->begin();
1681                 $args = func_get_args();
1682                 $function = array_shift( $args );
1683                 $oldIgnore = $this->ignoreErrors( true );
1684                 $tries = DEADLOCK_TRIES;
1685                 if ( is_array( $function ) ) {
1686                         $fname = $function[0];
1687                 } else {
1688                         $fname = $function;
1689                 }
1690                 do {
1691                         $retVal = call_user_func_array( $function, $args );
1692                         $error = $this->lastError();
1693                         $errno = $this->lastErrno();
1694                         $sql = $this->lastQuery();
1695
1696                         if ( $errno ) {
1697                                 if ( $this->wasDeadlock() ) {
1698                                         # Retry
1699                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1700                                 } else {
1701                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1702                                 }
1703                         }
1704                 } while( $this->wasDeadlock() && --$tries > 0 );
1705                 $this->ignoreErrors( $oldIgnore );
1706                 if ( $tries <= 0 ) {
1707                         $this->query( 'ROLLBACK', $myFname );
1708                         $this->reportQueryError( $error, $errno, $sql, $fname );
1709                         return false;
1710                 } else {
1711                         $this->query( 'COMMIT', $myFname );
1712                         return $retVal;
1713                 }
1714         }
1715
1716         /**
1717          * Do a SELECT MASTER_POS_WAIT()
1718          *
1719          * @param string $file the binlog file
1720          * @param string $pos the binlog position
1721          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1722          */
1723         function masterPosWait( MySQLMasterPos $pos, $timeout ) {
1724                 $fname = 'Database::masterPosWait';
1725                 wfProfileIn( $fname );
1726
1727                 # Commit any open transactions
1728                 if ( $this->mTrxLevel ) {
1729                         $this->immediateCommit();
1730                 }
1731
1732                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1733                         $wait = intval( ( $pos->pos - microtime(true) + $this->mFakeSlaveLag ) * 1e6 );
1734                         if ( $wait > $timeout * 1e6 ) {
1735                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
1736                                 wfProfileOut( $fname );
1737                                 return -1;
1738                         } elseif ( $wait > 0 ) {
1739                                 wfDebug( "Fake slave waiting $wait us\n" );
1740                                 usleep( $wait );
1741                                 wfProfileOut( $fname );
1742                                 return 1;
1743                         } else {
1744                                 wfDebug( "Fake slave up to date ($wait us)\n" );
1745                                 wfProfileOut( $fname );
1746                                 return 0;
1747                         }
1748                 }
1749
1750                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1751                 $encFile = $this->addQuotes( $pos->file );
1752                 $encPos = intval( $pos->pos );
1753                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
1754                 $res = $this->doQuery( $sql );
1755                 if ( $res && $row = $this->fetchRow( $res ) ) {
1756                         $this->freeResult( $res );
1757                         wfProfileOut( $fname );
1758                         return $row[0];
1759                 } else {
1760                         wfProfileOut( $fname );
1761                         return false;
1762                 }
1763         }
1764
1765         /**
1766          * Get the position of the master from SHOW SLAVE STATUS
1767          */
1768         function getSlavePos() {
1769                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1770                         $pos = new MySQLMasterPos( 'fake', microtime(true) - $this->mFakeSlaveLag );
1771                         wfDebug( __METHOD__.": fake slave pos = $pos\n" );
1772                         return $pos;
1773                 }
1774                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1775                 $row = $this->fetchObject( $res );
1776                 if ( $row ) {
1777                         return new MySQLMasterPos( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1778                 } else {
1779                         return false;
1780                 }
1781         }
1782
1783         /**
1784          * Get the position of the master from SHOW MASTER STATUS
1785          */
1786         function getMasterPos() {
1787                 if ( $this->mFakeMaster ) {
1788                         return new MySQLMasterPos( 'fake', microtime( true ) );
1789                 }
1790                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1791                 $row = $this->fetchObject( $res );
1792                 if ( $row ) {
1793                         return new MySQLMasterPos( $row->File, $row->Position );
1794                 } else {
1795                         return false;
1796                 }
1797         }
1798
1799         /**
1800          * Begin a transaction, committing any previously open transaction
1801          */
1802         function begin( $fname = 'Database::begin' ) {
1803                 $this->query( 'BEGIN', $fname );
1804                 $this->mTrxLevel = 1;
1805         }
1806
1807         /**
1808          * End a transaction
1809          */
1810         function commit( $fname = 'Database::commit' ) {
1811                 $this->query( 'COMMIT', $fname );
1812                 $this->mTrxLevel = 0;
1813         }
1814
1815         /**
1816          * Rollback a transaction.
1817          * No-op on non-transactional databases.
1818          */
1819         function rollback( $fname = 'Database::rollback' ) {
1820                 $this->query( 'ROLLBACK', $fname, true );
1821                 $this->mTrxLevel = 0;
1822         }
1823
1824         /**
1825          * Begin a transaction, committing any previously open transaction
1826          * @deprecated use begin()
1827          */
1828         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1829                 $this->begin();
1830         }
1831
1832         /**
1833          * Commit transaction, if one is open
1834          * @deprecated use commit()
1835          */
1836         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1837                 $this->commit();
1838         }
1839
1840         /**
1841          * Return MW-style timestamp used for MySQL schema
1842          */
1843         function timestamp( $ts=0 ) {
1844                 return wfTimestamp(TS_MW,$ts);
1845         }
1846
1847         /**
1848          * Local database timestamp format or null
1849          */
1850         function timestampOrNull( $ts = null ) {
1851                 if( is_null( $ts ) ) {
1852                         return null;
1853                 } else {
1854                         return $this->timestamp( $ts );
1855                 }
1856         }
1857
1858         /**
1859          * @todo document
1860          */
1861         function resultObject( $result ) {
1862                 if( empty( $result ) ) {
1863                         return false;
1864                 } elseif ( $result instanceof ResultWrapper ) {
1865                         return $result;
1866                 } elseif ( $result === true ) {
1867                         // Successful write query
1868                         return $result;
1869                 } else {
1870                         return new ResultWrapper( $this, $result );
1871                 }
1872         }
1873
1874         /**
1875          * Return aggregated value alias
1876          */
1877         function aggregateValue ($valuedata,$valuename='value') {
1878                 return $valuename;
1879         }
1880
1881         /**
1882          * @return string wikitext of a link to the server software's web site
1883          */
1884         function getSoftwareLink() {
1885                 return "[http://www.mysql.com/ MySQL]";
1886         }
1887
1888         /**
1889          * @return string Version information from the database
1890          */
1891         function getServerVersion() {
1892                 return mysql_get_server_info( $this->mConn );
1893         }
1894
1895         /**
1896          * Ping the server and try to reconnect if it there is no connection
1897          */
1898         function ping() {
1899                 if( !function_exists( 'mysql_ping' ) ) {
1900                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1901                         return true;
1902                 }
1903                 $ping = mysql_ping( $this->mConn );
1904                 if ( $ping ) {
1905                         return true;
1906                 }
1907
1908                 // Need to reconnect manually in MySQL client 5.0.13+
1909                 if ( version_compare( mysql_get_client_info(), '5.0.13', '>=' ) ) {
1910                         mysql_close( $this->mConn );
1911                         $this->mOpened = false;
1912                         $this->mConn = false;
1913                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
1914                         return true;
1915                 }
1916                 return false;
1917         }
1918
1919         /**
1920          * Get slave lag.
1921          * At the moment, this will only work if the DB user has the PROCESS privilege
1922          */
1923         function getLag() {
1924                 if ( !is_null( $this->mFakeSlaveLag ) ) {
1925                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
1926                         return $this->mFakeSlaveLag;
1927                 }
1928                 $res = $this->query( 'SHOW PROCESSLIST' );
1929                 # Find slave SQL thread
1930                 while ( $row = $this->fetchObject( $res ) ) {
1931                         /* This should work for most situations - when default db
1932                          * for thread is not specified, it had no events executed,
1933                          * and therefore it doesn't know yet how lagged it is.
1934                          *
1935                          * Relay log I/O thread does not select databases.
1936                          */
1937                         if ( $row->User == 'system user' &&
1938                                 $row->State != 'Waiting for master to send event' &&
1939                                 $row->State != 'Connecting to master' &&
1940                                 $row->State != 'Queueing master event to the relay log' &&
1941                                 $row->State != 'Waiting for master update' &&
1942                                 $row->State != 'Requesting binlog dump'
1943                                 ) {
1944                                 # This is it, return the time (except -ve)
1945                                 if ( $row->Time > 0x7fffffff ) {
1946                                         return false;
1947                                 } else {
1948                                         return $row->Time;
1949                                 }
1950                         }
1951                 }
1952                 return false;
1953         }
1954
1955         /**
1956          * Get status information from SHOW STATUS in an associative array
1957          */
1958         function getStatus($which="%") {
1959                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1960                 $status = array();
1961                 while ( $row = $this->fetchObject( $res ) ) {
1962                         $status[$row->Variable_name] = $row->Value;
1963                 }
1964                 return $status;
1965         }
1966
1967         /**
1968          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1969          */
1970         function maxListLen() {
1971                 return 0;
1972         }
1973
1974         function encodeBlob($b) {
1975                 return $b;
1976         }
1977
1978         function decodeBlob($b) {
1979                 return $b;
1980         }
1981
1982         /**
1983          * Override database's default connection timeout.
1984          * May be useful for very long batch queries such as
1985          * full-wiki dumps, where a single query reads out
1986          * over hours or days.
1987          * @param int $timeout in seconds
1988          */
1989         public function setTimeout( $timeout ) {
1990                 $this->query( "SET net_read_timeout=$timeout" );
1991                 $this->query( "SET net_write_timeout=$timeout" );
1992         }
1993
1994         /**
1995          * Read and execute SQL commands from a file.
1996          * Returns true on success, error string on failure
1997          * @param string $filename File name to open
1998          * @param callback $lineCallback Optional function called before reading each line
1999          * @param callback $resultCallback Optional function called for each MySQL result
2000          */
2001         function sourceFile( $filename, $lineCallback = false, $resultCallback = false ) {
2002                 $fp = fopen( $filename, 'r' );
2003                 if ( false === $fp ) {
2004                         return "Could not open \"{$filename}\".\n";
2005                 }
2006                 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback );
2007                 fclose( $fp );
2008                 return $error;
2009         }
2010
2011         /**
2012          * Read and execute commands from an open file handle
2013          * Returns true on success, error string on failure
2014          * @param string $fp File handle
2015          * @param callback $lineCallback Optional function called before reading each line
2016          * @param callback $resultCallback Optional function called for each MySQL result
2017          */
2018         function sourceStream( $fp, $lineCallback = false, $resultCallback = false ) {
2019                 $cmd = "";
2020                 $done = false;
2021                 $dollarquote = false;
2022
2023                 while ( ! feof( $fp ) ) {
2024                         if ( $lineCallback ) {
2025                                 call_user_func( $lineCallback );
2026                         }
2027                         $line = trim( fgets( $fp, 1024 ) );
2028                         $sl = strlen( $line ) - 1;
2029
2030                         if ( $sl < 0 ) { continue; }
2031                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
2032
2033                         ## Allow dollar quoting for function declarations
2034                         if (substr($line,0,4) == '$mw$') {
2035                                 if ($dollarquote) {
2036                                         $dollarquote = false;
2037                                         $done = true;
2038                                 }
2039                                 else {
2040                                         $dollarquote = true;
2041                                 }
2042                         }
2043                         else if (!$dollarquote) {
2044                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
2045                                         $done = true;
2046                                         $line = substr( $line, 0, $sl );
2047                                 }
2048                         }
2049
2050                         if ( '' != $cmd ) { $cmd .= ' '; }
2051                         $cmd .= "$line\n";
2052
2053                         if ( $done ) {
2054                                 $cmd = str_replace(';;', ";", $cmd);
2055                                 $cmd = $this->replaceVars( $cmd );
2056                                 $res = $this->query( $cmd, __METHOD__, true );
2057                                 if ( $resultCallback ) {
2058                                         call_user_func( $resultCallback, $res );
2059                                 }
2060
2061                                 if ( false === $res ) {
2062                                         $err = $this->lastError();
2063                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2064                                 }
2065
2066                                 $cmd = '';
2067                                 $done = false;
2068                         }
2069                 }
2070                 return true;
2071         }
2072
2073
2074         /**
2075          * Replace variables in sourced SQL
2076          */
2077         protected function replaceVars( $ins ) {
2078                 $varnames = array(
2079                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2080                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2081                         'wgDBadminuser', 'wgDBadminpassword', 'wgDBTableOptions',
2082                 );
2083
2084                 // Ordinary variables
2085                 foreach ( $varnames as $var ) {
2086                         if( isset( $GLOBALS[$var] ) ) {
2087                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2088                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2089                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2090                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2091                         }
2092                 }
2093
2094                 // Table prefixes
2095                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2096                         array( &$this, 'tableNameCallback' ), $ins );
2097                 return $ins;
2098         }
2099
2100         /**
2101          * Table name callback
2102          * @private
2103          */
2104         protected function tableNameCallback( $matches ) {
2105                 return $this->tableName( $matches[1] );
2106         }
2107
2108         /*
2109          * Build a concatenation list to feed into a SQL query
2110         */
2111         function buildConcat( $stringList ) {
2112                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2113         }
2114
2115 }
2116
2117 /**
2118  * Database abstraction object for mySQL
2119  * Inherit all methods and properties of Database::Database()
2120  *
2121  * @addtogroup Database
2122  * @see Database
2123  */
2124 class DatabaseMysql extends Database {
2125         # Inherit all
2126 }
2127
2128 /******************************************************************************
2129  * Utility classes
2130  *****************************************************************************/
2131
2132 /**
2133  * Utility class.
2134  * @addtogroup Database
2135  */
2136 class DBObject {
2137         public $mData;
2138
2139         function DBObject($data) {
2140                 $this->mData = $data;
2141         }
2142
2143         function isLOB() {
2144                 return false;
2145         }
2146
2147         function data() {
2148                 return $this->mData;
2149         }
2150 }
2151
2152 /**
2153  * Utility class
2154  * @addtogroup Database
2155  *
2156  * This allows us to distinguish a blob from a normal string and an array of strings
2157  */
2158 class Blob {
2159         private $mData;
2160         function __construct($data) {
2161                 $this->mData = $data;
2162         }
2163         function fetch() {
2164                 return $this->mData;
2165         }
2166 }
2167
2168 /**
2169  * Utility class.
2170  * @addtogroup Database
2171  */
2172 class MySQLField {
2173         private $name, $tablename, $default, $max_length, $nullable,
2174                 $is_pk, $is_unique, $is_key, $type;
2175         function __construct ($info) {
2176                 $this->name = $info->name;
2177                 $this->tablename = $info->table;
2178                 $this->default = $info->def;
2179                 $this->max_length = $info->max_length;
2180                 $this->nullable = !$info->not_null;
2181                 $this->is_pk = $info->primary_key;
2182                 $this->is_unique = $info->unique_key;
2183                 $this->is_multiple = $info->multiple_key;
2184                 $this->is_key = ($this->is_pk || $this->is_unique || $this->is_multiple);
2185                 $this->type = $info->type;
2186         }
2187
2188         function name() {
2189                 return $this->name;
2190         }
2191
2192         function tableName() {
2193                 return $this->tableName;
2194         }
2195
2196         function defaultValue() {
2197                 return $this->default;
2198         }
2199
2200         function maxLength() {
2201                 return $this->max_length;
2202         }
2203
2204         function nullable() {
2205                 return $this->nullable;
2206         }
2207
2208         function isKey() {
2209                 return $this->is_key;
2210         }
2211
2212         function isMultipleKey() {
2213                 return $this->is_multiple;
2214         }
2215
2216         function type() {
2217                 return $this->type;
2218         }
2219 }
2220
2221 /******************************************************************************
2222  * Error classes
2223  *****************************************************************************/
2224
2225 /**
2226  * Database error base class
2227  * @addtogroup Database
2228  */
2229 class DBError extends MWException {
2230         public $db;
2231
2232         /**
2233          * Construct a database error
2234          * @param Database $db The database object which threw the error
2235          * @param string $error A simple error message to be used for debugging
2236          */
2237         function __construct( Database &$db, $error ) {
2238                 $this->db =& $db;
2239                 parent::__construct( $error );
2240         }
2241 }
2242
2243 /**
2244  * @addtogroup Database
2245  */
2246 class DBConnectionError extends DBError {
2247         public $error;
2248
2249         function __construct( Database &$db, $error = 'unknown error' ) {
2250                 $msg = 'DB connection error';
2251                 if ( trim( $error ) != '' ) {
2252                         $msg .= ": $error";
2253                 }
2254                 $this->error = $error;
2255                 parent::__construct( $db, $msg );
2256         }
2257
2258         function useOutputPage() {
2259                 // Not likely to work
2260                 return false;
2261         }
2262
2263         function useMessageCache() {
2264                 // Not likely to work
2265                 return false;
2266         }
2267
2268         function getText() {
2269                 return $this->getMessage() . "\n";
2270         }
2271
2272         function getLogMessage() {
2273                 # Don't send to the exception log
2274                 return false;
2275         }
2276
2277         function getPageTitle() {
2278                 global $wgSitename;
2279                 return "$wgSitename has a problem";
2280         }
2281
2282         function getHTML() {
2283                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
2284                 global $wgSitename, $wgServer, $wgMessageCache;
2285
2286                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
2287                 # Hard coding strings instead.
2288
2289                 $noconnect = "<p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
2290                 $mainpage = 'Main Page';
2291                 $searchdisabled = <<<EOT
2292 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
2293 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
2294 EOT;
2295
2296                 $googlesearch = "
2297 <!-- SiteSearch Google -->
2298 <FORM method=GET action=\"http://www.google.com/search\">
2299 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
2300 <A HREF=\"http://www.google.com/\">
2301 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
2302 border=\"0\" ALT=\"Google\"></A>
2303 </td>
2304 <td>
2305 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
2306 <INPUT type=submit name=btnG VALUE=\"Google Search\">
2307 <font size=-1>
2308 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
2309 <input type='hidden' name='ie' value='$2'>
2310 <input type='hidden' name='oe' value='$2'>
2311 </font>
2312 </td></tr></TABLE>
2313 </FORM>
2314 <!-- SiteSearch Google -->";
2315                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
2316
2317                 # No database access
2318                 if ( is_object( $wgMessageCache ) ) {
2319                         $wgMessageCache->disable();
2320                 }
2321
2322                 if ( trim( $this->error ) == '' ) {
2323                         $this->error = $this->db->getProperty('mServer');
2324                 }
2325
2326                 $text = str_replace( '$1', $this->error, $noconnect );
2327                 $text .= wfGetSiteNotice();
2328
2329                 if($wgUseFileCache) {
2330                         if($wgTitle) {
2331                                 $t =& $wgTitle;
2332                         } else {
2333                                 if($title) {
2334                                         $t = Title::newFromURL( $title );
2335                                 } elseif (@/**/$_REQUEST['search']) {
2336                                         $search = $_REQUEST['search'];
2337                                         return $searchdisabled .
2338                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
2339                                           $wgInputEncoding ), $googlesearch );
2340                                 } else {
2341                                         $t = Title::newFromText( $mainpage );
2342                                 }
2343                         }
2344
2345                         $cache = new HTMLFileCache( $t );
2346                         if( $cache->isFileCached() ) {
2347                                 // @todo, FIXME: $msg is not defined on the next line.
2348                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
2349                                         $cachederror . "</b></p>\n";
2350
2351                                 $tag = '<div id="article">';
2352                                 $text = str_replace(
2353                                         $tag,
2354                                         $tag . $msg,
2355                                         $cache->fetchPageText() );
2356                         }
2357                 }
2358
2359                 return $text;
2360         }
2361 }
2362
2363 /**
2364  * @addtogroup Database
2365  */
2366 class DBQueryError extends DBError {
2367         public $error, $errno, $sql, $fname;
2368
2369         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
2370                 $message = "A database error has occurred\n" .
2371                   "Query: $sql\n" .
2372                   "Function: $fname\n" .
2373                   "Error: $errno $error\n";
2374
2375                 parent::__construct( $db, $message );
2376                 $this->error = $error;
2377                 $this->errno = $errno;
2378                 $this->sql = $sql;
2379                 $this->fname = $fname;
2380         }
2381
2382         function getText() {
2383                 if ( $this->useMessageCache() ) {
2384                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
2385                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
2386                 } else {
2387                         return $this->getMessage();
2388                 }
2389         }
2390
2391         function getSQL() {
2392                 global $wgShowSQLErrors;
2393                 if( !$wgShowSQLErrors ) {
2394                         return $this->msg( 'sqlhidden', 'SQL hidden' );
2395                 } else {
2396                         return $this->sql;
2397                 }
2398         }
2399
2400         function getLogMessage() {
2401                 # Don't send to the exception log
2402                 return false;
2403         }
2404
2405         function getPageTitle() {
2406                 return $this->msg( 'databaseerror', 'Database error' );
2407         }
2408
2409         function getHTML() {
2410                 if ( $this->useMessageCache() ) {
2411                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
2412                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
2413                 } else {
2414                         return nl2br( htmlspecialchars( $this->getMessage() ) );
2415                 }
2416         }
2417 }
2418
2419 /**
2420  * @addtogroup Database
2421  */
2422 class DBUnexpectedError extends DBError {}
2423
2424
2425 /**
2426  * Result wrapper for grabbing data queried by someone else
2427  * @addtogroup Database
2428  */
2429 class ResultWrapper implements Iterator {
2430         var $db, $result, $pos = 0, $currentRow = null;
2431
2432         /**
2433          * Create a new result object from a result resource and a Database object
2434          */
2435         function ResultWrapper( $database, $result ) {
2436                 $this->db = $database;
2437                 if ( $result instanceof ResultWrapper ) {
2438                         $this->result = $result->result;
2439                 } else {
2440                         $this->result = $result;
2441                 }
2442         }
2443
2444         /**
2445          * Get the number of rows in a result object
2446          */
2447         function numRows() {
2448                 return $this->db->numRows( $this->result );
2449         }
2450
2451         /**
2452          * Fetch the next row from the given result object, in object form.
2453          * Fields can be retrieved with $row->fieldname, with fields acting like
2454          * member variables.
2455          *
2456          * @param $res SQL result object as returned from Database::query(), etc.
2457          * @return MySQL row object
2458          * @throws DBUnexpectedError Thrown if the database returns an error
2459          */
2460         function fetchObject() {
2461                 return $this->db->fetchObject( $this->result );
2462         }
2463
2464         /**
2465          * Fetch the next row from the given result object, in associative array
2466          * form.  Fields are retrieved with $row['fieldname'].
2467          *
2468          * @param $res SQL result object as returned from Database::query(), etc.
2469          * @return MySQL row object
2470          * @throws DBUnexpectedError Thrown if the database returns an error
2471          */
2472         function fetchRow() {
2473                 return $this->db->fetchRow( $this->result );
2474         }
2475
2476         /**
2477          * Free a result object
2478          */
2479         function free() {
2480                 $this->db->freeResult( $this->result );
2481                 unset( $this->result );
2482                 unset( $this->db );
2483         }
2484
2485         /**
2486          * Change the position of the cursor in a result object
2487          * See mysql_data_seek()
2488          */
2489         function seek( $row ) {
2490                 $this->db->dataSeek( $this->result, $row );
2491         }
2492
2493         /*********************
2494          * Iterator functions
2495          * Note that using these in combination with the non-iterator functions
2496          * above may cause rows to be skipped or repeated.
2497          */
2498
2499         function rewind() {
2500                 if ($this->numRows()) {
2501                         $this->db->dataSeek($this->result, 0);
2502                 }
2503                 $this->pos = 0;
2504                 $this->currentRow = null;
2505         }
2506
2507         function current() {
2508                 if ( is_null( $this->currentRow ) ) {
2509                         $this->next();
2510                 }
2511                 return $this->currentRow;
2512         }
2513
2514         function key() {
2515                 return $this->pos;
2516         }
2517
2518         function next() {
2519                 $this->pos++;
2520                 $this->currentRow = $this->fetchObject();
2521                 return $this->currentRow;
2522         }
2523
2524         function valid() {
2525                 return $this->current() !== false;
2526         }
2527 }
2528
2529 class MySQLMasterPos {
2530         var $file, $pos;
2531
2532         function __construct( $file, $pos ) {
2533                 $this->file = $file;
2534                 $this->pos = $pos;
2535         }
2536
2537         function __toString() {
2538                 return "{$this->file}/{$this->pos}";
2539         }
2540 }